(1) Field of the Invention
The present invention pertains to a manually operated liquid foaming dispenser. Specifically, the invention pertains to a manually operated pump that is attached to the top of a bottle of liquid and that pumps and mixes both the liquid and air to create a foam from the liquid and dispense the foam. The dispenser includes a pump housing containing an air pump chamber and a liquid pump chamber, and a pump plunger that is manually reciprocated in both the air pump chamber and the liquid pump chamber. An air piston and a liquid piston are mounted on the plunger and are reciprocated by the plunger in the respective air pump chamber and liquid pump chamber.
(2) Description of the Related Art
There are various different types of manually operated liquid dispensers that pump liquid from containers attached to the dispensers and generate a foam from the liquid that is discharged from the dispensers. A familiar example of these types of foam generating liquid dispensers is the manually operated trigger sprayer. Trigger sprayers are designed to be comfortably held in one hand of a user with the trigger of the trigger sprayer being easily manipulated by the fingers of the user's hand. Pivoting movement of the trigger sprayer's trigger operates a liquid pump in the trigger sprayer. Operation of the pump draws liquid from a bottle container connected to the trigger sprayer and discharges the liquid in a spray pattern from a discharge nozzle of the trigger sprayer. The discharge nozzle of this type of trigger sprayer typically has an obstruction positioned in the path of the liquid sprayed from the trigger sprayer. The liquid spray hitting the obstruction mixes the liquid spray with the air of the exterior environment of the sprayer and thereby produces a foam that is discharged from the trigger sprayer.
The foaming liquid trigger sprayer of the type described above is well suited for dispensing a foam produced from a liquid where the desired foaming of the liquid is marginal, for example in dispensing foaming liquid kitchen or bathroom cleansers. However, the typical foaming liquid trigger sprayer cannot produce a more dense foam, such as that of shaving cream.
To produce a more dense foam dispensed from a manually operated foaming liquid dispenser requires that both the liquid and the air be pumped through the obstruction that produces the foam. Foaming liquid dispensers of this type comprise a pump housing containing an air pump chamber and a liquid pump chamber, and a pump plunger that is manually reciprocated in the pump housing. An air piston is mounted on the pump plunger and is received in the air pump chamber for reciprocating movement, and a liquid piston is mounted on the pump plunger and is received in the liquid pump chamber for reciprocating movement. Movement of the pump plunger toward a retracted position into the pump housing causes the air piston to move into the air pump chamber and exert a force on the air in the chamber and causes the liquid piston to move into the liquid pump chamber and exert a force on the liquid in the chamber. A pair of valves control the flow of air and liquid from the respective air pump chamber and liquid pump chamber through a center discharge passage of the pump plunger where the air and liquid is mixed to generate the foam. The foam is then discharged from the dispenser.
A spring of the foaming liquid dispenser causes the pump plunger to move from its retracted position in the pump housing to an extended position where the top portion of the pump plunger projects outwardly from the top of the pump housing. This movement of the pump plunger causes the air piston and the liquid piston to move out of their respective air pump chamber and liquid pump chamber, expanding the interior volumes of the two chambers. This creates vacuums in the two pump chambers that draw air into the air pump chamber interior volume and draw liquid into the liquid pump chamber interior volume. Valve assemblies are typically employed in controlling the flow of air and liquid into the respective air pump chamber and liquid pump chamber as their interior volumes are increased by the movement of the pump plunger. The valves allow air and liquid to enter the respective air pump chamber and liquid pump chamber as the pump plunger moves to its extended position, and the valves close preventing air and liquid from passing through the valves when the pump plunger is moved to its retracted position in the pump housing.
A substantial number of manually operated foaming liquid dispensers are manufactured to meet the needs of consumers. Reducing the manufacturing costs of a manually operated foaming liquid dispenser to only a small degree, for example by one penny or a fraction of a penny, significantly reduces the manufacturing costs of manually operated foaming liquid dispensers due to the significant number of the dispensers manufactured. Thus, a change in the design of a manually operated foaming liquid dispenser that results in even a small reduction in its manufacturing costs could result in a significant benefit to the manufacturing of manually operated foaming liquid dispensers.